…[this] week, the Supreme Court will hear one of the most important free speech cases in years, a case of special concern to libertarians and conservatives, small business-owners, artisans, and religious believers. Masterpiece Cakeshop v.Colorado Civil Rights Commission involves Jack Phillips, a baker who claims a First Amendment right not to be compelled to design and create custom wedding cakes for same-sex weddings. Many legal commentators think the case is either a very close call or a certain defeat for Phillips.

In fact, Phillips’s case is very strong. It is based on freedom-of-speech doctrines favored by conservatives and liberals alike. One argument for Phillips in particular survives the best objections leveled in briefs filed by the Colorado Civil Rights Commission, by the ACLU (on behalf of the couple who sought the cake), and by several constitutional law scholars.

That argument rests on the widely acknowledged principle that freedom of speech has to include the freedom not to speak. You aren’t free to express your convictions authentically if the state can make you affirm its own orthodoxies. Thus, for more than seventy years, in cases widely seen as more American than apple pie, the Supreme Court has said government can’t force you to say, do, or make something that carries a message you reject. Applying that principle, it has held that the government can’t force Jehovah’s Witnesses to salute the flag. It can’t force newspapers to carry columns by politicians criticized in their pages. It can’t force drivers to carry license plates with a state-imposed (though utterly banal) slogan (“Live Free or Die”). It can’t force companies to include third-party messages in their billing envelopes. Political majorities are entitled to enact their beliefs into law, but not to force dissenting minorities to affirm those or anyone else’s beliefs in word or deed. That would involve “compelled speech,” which is generally unconstitutional.